Embodiments of the disclosure relate generally to electric drive systems and energy management methods, useful in a variety of propulsion systems such as an electric vehicle (EV) system.
With the increased concern about energy crisis and environmental pollution caused by the fossil fuel exhaust, there is a growing interest in developing electric-powered vehicles, in which conventional fossil energy may be replaced by energy sources such as lead-acid batteries, fuel cells, flywheel batteries, etc. Electric drive system is one of the key components in the electric-powered vehicles. In the electric drive system, several kinds of AC motors such as induction motor (IM), interior permanent motor (IPM) and switched reluctance motor (SRC) are widely used for converting electric power into mechanical torques. It is desired that the propulsion system may have features of high efficiency, and high performance with low cost. These features may be achieved by choosing appropriate energy sources, appropriate AC motors, and then combining them together in an appropriate structure.
Currently, most of the electric drive systems include a single energy storage system (ESS) or a single motor, or a dual ESS with a single motor. However, on the one hand, a single ESS may not satisfy both the energy and power requirements such as low energy, slow charging rate, and a shorter life due to its own limitation of charge/discharge characteristics. On the other hand, a single motor may not work with a high efficiency across the entire operating range. It will cause problems of oversize, high cost, and low efficiency in order to meet high performances such as a short acceleration time and a long running mileage of the propulsion system.
Therefore, it is desirable to provide systems and methods to address the above-mentioned problems.